After two years’ research, we now have a ________ better understanding of the disease.
Do you know the man____ is talking with Tom?
A dictionary is a book ______ gives the meanings of words.
The old town has narrow streets and small houses ________ are built close to each other.
Do you want a friend ______ you could tell everything to?
—May I see your ticket, please? I think you ________ in my seat.—Oh, sorry. My seat is upstairs.